East Anglia ONE North Offshore Windfarm

Transcription

1 East Anglia ONE North Offshore Windfarm Chapter 10 Fish and Shellfish Ecology Preliminary Environmental Information Volume 1 Document Reference: EA1N-DEVWF-ENV-REP-IBR Prepared by: Paolo Pizzolla :48:34 Z Checked by: Ian Mackay :39:28 Z Approved by: Helen Walker :30:10 Z

2 Revision Summary Rev Date Document Status Prepared by Checked by Approved by 01 11/01/2019 For issue Paolo Pizzolla Ian MacKay Helen Walker Description of Revisions Rev Page Section Description 01 n/a n/a Final draft EA1N-DEVWF-ENV-REP-IBR Chapter 10 Fish and Shellfish Ecology Page i

3 Table of Contents 10 Fish and Shellfish Ecology Introduction Consultation Scope Assessment Methodology Existing Environment Potential Impacts Cumulative Impacts Transboundary Impacts Inter-relationships Interactions Summary References 134 EA1N-DEVWF-ENV-REP-IBR Chapter 10 Fish and Shellfish Ecology Page ii

4 Chapter 10 Fish and Shellfish Ecology figures are presented in Volume 2 and listed in the table below. Figure number Title 10.1 East Anglia ONE North windfarm and offshore cable corridor study areas 10.2 Average number (catch per standardised haul) of Dover sole from IBTS survey data ( ) 10.3 Dover sole spawning and nursery grounds 10.4 Average number (catch per standardised haul) of Plaice from IBTS survey data ( ) 10.5 Plaice spawning and nursery grounds 10.6 Average number (catch per standardised haul) of Cod from IBTS survey data ( ) 10.7 Cod spawning and nursery grounds 10.8 Average number (catch per standardised haul) of Whiting from IBTS survey data ( ) 10.9 Whiting spawning and nursery grounds Average number (catch per standardised haul) of Lemon sole from IBTS survey data ( ) Lemon sole spawning and nursery grounds Seabass historic fishing areas Average number (catch per standardised haul) of Herring from IBTS survey data ( ) Herring spawning and nursery grounds IHLS herring small larvae abundance ( ) IHLS herring small larvae abundance ( ) IHLS herring small larvae abundance ( ) and all herring larvae ( ) Average number (catch per standardised haul) of Mackerel from IBTS survey data ( ) Mackerel spawning and nursery grounds Average number (catch per standardised haul) of Sprat from IBTS survey data ( ) Sprat spawning and nursery grounds EA1N-DEVWF-ENV-REP-IBR Chapter 10 Fish and Shellfish Ecology Page iii

5 Figure number Title Average number (catch per standardised haul) of Greater sandeel from IBTS survey data ( ) Average number (catch per standardised haul) of Lesser sandeel rom IBTS survey data ( ) Average number (catch per standardised haul) of smooth sandeel from IBTS survey data ( ) Average number (catch per standardised haul) of Small sandeel from IBTS survey data ( ) Sandeel spawning and nursery grounds Average number (catch per standardised haul) of Thornback ray from IBTS survey data ( ) Tope and Thornback ray spawning and nursery grounds Average number (catch per standardised haul) of Spotted ray from IBTS survey data ( ) Average number (catch per standardised haul) of Blonde ray from IBTS survey data ( ) Average number (catch per standardised haul) of Starry smoothhound from IBTS survey data ( ) Average number (catch per standardised haul) of Smoothhound from IBTS survey data ( ) Average number (catch per standardised haul) of Spurdog from IBTS survey data ( ) Dover sole spawning grounds in relation to the worst case TTS impact range for pin pile installation Plaice spawning grounds in relation to the worst case TTS impact range for pin pile installation Cod spawning grounds in relation to the worst case TTS impact range for pin pile installation Whiting spawning grounds in relation to the worst case TTS impact range for pin pile installation Lemon sole spawning grounds in relation to the worst case TTS impact range for pin pile installation Herring spawning grounds in relation to the worst case TTS impact range for pin pile installation Sprat spawning grounds in relation to the worst case TTS impact range for pin EA1N-DEVWF-ENV-REP-IBR Chapter 10 Fish and Shellfish Ecology Page iv

6 Figure number Title pile installation Sandeels spawning grounds in relation to the worst case TTS impact range for pin pile installation Mackerel spawning grounds in relation to the worst case TTS impact range for pin pile installation Seabass spawning grounds in relation to the worst case TTS impact range for pin pile installation Thornback and tope spawning grounds in relation to the worst case TTS impact range for pin pile installation Chapter 10 Fish and Shellfish Ecology appendices are presented in Volume 3 and listed in the table below. Appendix number Title 10.1 Fish and Shellfish Ecology Technical Appendix EA1N-DEVWF-ENV-REP-IBR Chapter 10 Fish and Shellfish Ecology Page v

7 Glossary of Acronyms AC BOEM Cefas CPUE COWRIE DATRAS DCO Defra DWR EIA EMF EMFF EMODnet EPP ES ESFJC ETG EU EUNIS FAD FEPA FSA GOV HRA HVAC ICES IBTS IEEM IFCA IHLS IMARES JNCC MarLIN MARPOL MarSEA MCEU MCZ MMMP MMO MPS MSFD nm NMFS NPS OOOMP ORJIP OSPAR OWF PEMP Alternating Current Bureau of Ocean Energy Management Centre for Environment Fisheries and Aquaculture Science Catch per Unit Effort Collaborative Offshore Wind Research into the Environment Database of Trawl Surveys Development Consent Order Department for Environment Deep Water Route Environmental Impact Assessment Electromagnetic Fields European Maritime Fisheries Funded European Marine Observation and Data Network Evidence Plan Process Environmental Statement Eastern Sea Fisheries Joint Commission Expert Topic Group European Union European Union Nature Information System Fish Aggregation Device Food and Environmental Protection Act Food Standards Agency Grande Ouverture Verticale Habitats Regulations Assessment High Voltage Alternating Current International Council for Exploration at Sea International Beam Trawl Survey Institute of Ecology and Environmental Management Inshore Fisheries Conservation Authorities International Herring Larvae Survey Institute for Marine Resources and Ecosystem Studies Joint Nature Conservation Committee Marine Life Information network The International Convention for the Prevention of Pollution from Ships, Marine Evidence Based Sensitivity Assessment Marine Consent and Environment Unit Marine Conservation Zone Marine Mammals Mitigation Plan Marine Management Organisation Marine Policy Statement Marine Strategy Framework Directive Nautical Miles National Marine Fisheries Service National Policy Statement Outline Offshore Operations and Maintenance Plan Offshore Renewables Joint Industry Programme Convention for the Protection of the Marine Environment of the North Atlantic Offshore Wind Farm Project Environmental Management Plan EA1N-DEVWF-ENV-REP-IBR Chapter 10 Fish and Shellfish Ecology Page vi

8 REC SAC SNCB SPA SPR SSCs TAC TSS TTS WFD WTG Regional Environmental Characterisation Special Area of Conservation Statutory Nature Conservation Body Special Protection Area ScottishPower Renewables Suspended Sediment Concentrations Total Allowable Catches Traffic Separation Scheme Temporary Threshold Shift Water Framework Directive Wind Turbine Generator EA1N-DEVWF-ENV-REP-IBR Chapter 10 Fish and Shellfish Ecology Page vii

9 Glossary of Terminology Applicant Beam trawl Bioelectric Bony fish Clupeid Construction operation and maintenance platform Crustacean Demersal Development Area Diadramous East Anglia ONE North project East Anglia ONE North windfarm site Elasmobranch European site Evidence Plan Process Gadoid Gravid Horizontal directional drilling (HDD) Inter-array cables Landfall Mollusc Natura 2000 site East Anglia ONE North Limited. A trawl net whose lateral spread during trawling is maintained by a beam across its mouth. Relating to electricity or electrical phenomena produced within living organisms. Any of a major taxon (class Osteichthyes or superclass Teleostomi) comprising fishes with a bony rather than a cartilaginous skeleton. Any of various fishes of the family Clupeidae, which includes the herrings, sprats, sardines and shads. A fixed offshore structure required for construction, operation, and maintenance personnel and activities. An arthropod of the large, mainly aquatic group Crustacea, such as a crab, lobster, shrimp, or barnacle. Living on or near the seabed. The area comprising the Indicative Onshore Development Area and the Offshore Development Area Migrating between fresh and salt water. The proposed project consisting of up to 67 wind turbines, up to four offshore electrical platforms, up to one construction operation and maintenance platform, inter-array cables, platform link cables, up to one operational meteorological mast, up to two offshore export cables, fibre optic cables, landfall infrastructure, onshore cables and ducts, onshore substation, and National Grid infrastructure. The offshore area within which wind turbines and offshore platforms will be located. Any cartilaginous fish of the subclass Elasmobranchii which includes sharks, rays and skates. Sites designated for nature conservation under the Habitats Directive and Birds Directive, as defined in regulation 8 of the Conservation of Habitats and Species Regulations 2017 and regulation 18 of the Conservation of Offshore Marine Habitats and Species Regulations These include candidate Special Areas of Conservation, Sites of Community Importance, Special Areas of Conservation and Special Protection Areas. A voluntary consultation process with specialist stakeholders to agree the approach to the EIA and the information required to support HRA. A bony fish of an order (Gadiformes) that comprises the cods, hakes, and their relatives. Carrying eggs or young A method of cable installation where the cable is drilled beneath a feature without the need for trenching. Offshore cables which link the wind turbines to each other and the offshore electrical platforms, these cables will include fibre optic cables. The area (from Mean Low Water Springs) where the offshore export cables would make contact with land, and connect to the onshore cables. An invertebrate of a large phylum which includes snails, slugs, mussels, and octopuses. They have a soft unsegmented body and live in aquatic or damp habitats, and most kinds have an external calcareous shell. A site forming part of the network of sites made up of Special Areas of Conservation and Special Protection Areas designated respectively under the Habitats Directive and Birds Directive. EA1N-DEVWF-ENV-REP-IBR Chapter 10 Fish and Shellfish Ecology Page viii

10 Offshore cable corridor Offshore development area Offshore electrical infrastructure Offshore electrical platform Offshore export cables Offshore infrastructure Offshore platform Otter trawl Ovigerous Pelagic Piscivorous Platform link cable Scour protection Species of Conservation Interest Swim bladder This is the area which will contain the offshore export cable between offshore electrical platforms and landfall jointing bay. The East Anglia ONE North windfarm site and offshore cable corridor (up to Mean High Water Springs). The transmission assets required to export generated electricity to shore. This includes inter-array cables from the wind turbines to the offshore electrical platforms, offshore electrical platforms, and export cables from the offshore electrical platforms to the landfall. A fixed structure located within the windfarm area, containing electrical equipment to aggregate the power from the wind turbines and convert it into a more suitable form for export to shore. The cables which would bring electricity from the offshore electrical platforms to the landfall, these cables will include fibre optic cables. All of the offshore infrastructure including wind turbines, platforms, and cables. This is the area which will contain the offshore export cable between offshore electrical platforms and landfall jointing bay. A trawl net fitted with two otter boards which maintain the horizontal opening of the net. Carrying or bearing eggs. Living in the water column Feeding on fish Electrical cable which links one or more offshore platforms, these cables will include fibre optic cables. Protective materials to avoid sediment being eroded away from the base of the foundations as a result of the flow of water. Marine species that are particularly threatened, rare, or declining. A gas-filled sac present in the body of many bony fish, used to maintain and control buoyancy. EA1N-DEVWF-ENV-REP-IBR Chapter 10 Fish and Shellfish Ecology Page ix

11 10 Fish and Shellfish Ecology 10.1 Introduction This chapter of the (PEIR) describes the fish and shellfish ecology baseline ( existing environment ) in relation to the proposed East Anglia ONE North project and includes an assessment of the potential impacts on these receptors during the construction, operation and maintenance (O&M) and decommissioning phases, along with proposed mitigation measures, where appropriate. This chapter of the PEIR has been written by Royal HaskoningDHV, and has taken account of guidance provided in the National Policy Statements (NPS) for Overarching Energy EN-1 (Biodiversity and Geological Conservation) and Renewable Energy Infrastructure EN-3 (Offshore Wind Farm Impacts Fish). The characterisation of the existing environment and impact assessment have been derived using data and information from a number of sources, including the scientific literature, fisheries statistical datasets, and fish and shellfish surveys undertaken within the former East Anglia Zone. Consultation has been undertaken with statutory and non-statutory stakeholders including the Marine Management Organisation (MMO), Centre for Environment, Fisheries and Aquaculture Science (Cefas), Eastern Inshore Fisheries and Conservation Authority (EIFCA), Natural England and commercial fisheries organisations. Impacts assessed on fish and shellfish ecology have potential interrelationships with the following offshore environment topics: Chapter 7 Marine Geology, Oceanography and Physical Processes; Chapter 8 Marine Water and Sediment Quality; Chapter 9 Benthic Ecology; Chapter 11 Marine Mammals; Chapter 12 Offshore Ornithology; and Chapter 13 Commercial Fisheries Consultation Consultation is a key driver of the Environmental Impact Assessment (EIA) process, and continues throughout the lifecycle of a project, from its initial stages through to consent and post-consent. EA1N-DEVWF-ENV-REP-IBR Chapter 10 Fish and Shellfish Ecology Page 1

12 To date, consultation with regards to fish and shellfish ecology has been undertaken via Expert Topic Group (ETG), described within Chapter 5 EIA Methodology, with meetings held in April 2017, and through the East Anglia TWO Scoping Report (SPR 2017). Feedback received through this process has been considered in preparing the the PEIR where appropriate and this chapter will be updated following the next stage of consultation for the final assessment submitted with the Development Consent Order (DCO) application. Table 10.1 outlines the scoping responses received in relation to fish and shellfish ecology and provides a summary of the response to each comment raised. Consultation specific to Marine Water and Sediment Quality, Marine Mammals, Offshore Ornithology and Commerical Fisheries are provided in Chapter 8 Marine Water and Sediment Quality, Chapter 11 Marine Mammals, Chapter 12 Ornithology and Chapter 13 Commerical Fisheries, respectively. Table 10.1 Consultation Responses Consultee Date/ Document Comment Response / where addressed in the PEIR Natural England 08/12/2017 Scoping Response As part of the evidence plan process NE, CEFAS and MMO advised EA1N and EA2 not to scope out re-suspended contaminants without site specific data to justify that contamination levels were low. We note that this has been provided and EA1N and EA2 are collecting site specific data, so this may be scoped out at a later date dependant on findings. This is discussed in section Marine Management Organisation 07/12/2017 Scoping Response The scoping report refers specifically to fish ecology only. Please could SPR confirm that potential impacts on shellfish will also be included in the ES. Shellfish have been included in the assessment in section Marine Management Organisation 07/12/2017 Scoping Response It should be noted that the proposed development is within a recognised spawning and nursery area for whiting and mackerel. Noted, these species have been included in our assessment and addressed in Table and Appendix 10.1 Marine Management Organisation 07/12/2017 Scoping Response The MMO welcomes the recognition of the seabass special protection measures and confirmation that the PEI will Noted, for further discussion regarding seabass habitats see section and EA1N-DEVWF-ENV-REP-IBR Chapter 10 Fish and Shellfish Ecology Page 2

13 Consultee Date/ Document Comment Response / where addressed in the PEIR consider important seabass habitats. Appendix Marine Management Organisation 07/12/2017 Scoping Response The Scoping Report recognises that there are areas of sandbanks inshore of the ECR corridor area of search which is supporting features of the Outer Thames Estuary SPA which are of importance to foraging red throated diver Gavia stellata. Sandeels are a prey species of red throated diver. If the ornithological impact assessment indicates that sandeel are a prey item for seabirds which may be impacted by the wind farm, the PEI should consider and assess the importance of sandeel habitat present. Section of Chapter 12 Offshore Ornithology indicates that sandeel are a prey species for various seabirds which may be impacted by the proposed East Anglia ONE North project. The importance of sandeel habitat is considered in Appendix Marine Management Organisation 07/12/2017 Scoping Response The MMO recommends that clarification regarding the scoping in or out of potential re-suspended contaminated sediment impacts on fish and shellfish ecology should be provided in the PEI following analysis of forthcoming benthic survey data. This is discussed in section Marine Management Organisation 07/12/2017 Scoping Response The potential impact of underwater noise from operational turbines has been scoped in for marine mammals but not for fish receptors. Appendix 2.3 Fish Ecology Method Statement appears to suggest that underwater noise during the operational phase will be considered with regard to fish/shellfish receptors, given that the qualification of the magnitude of this impact is intended to be guided by the results of noise assessments. The MMO recommends that consideration of the potential impact of operational underwater noise is clarified for fish and shellfish receptors in the ES following completion of noise assessments. The potential impact of operational underwater noise is discussed in section EA1N-DEVWF-ENV-REP-IBR Chapter 10 Fish and Shellfish Ecology Page 3

14 Consultee Date/ Document Comment Response / where addressed in the PEIR Marine Management Organisation 07/12/2017 Scoping Response The most appropriate noise exposure criteria for fish are those published by Popper et al. (2014). The MMO recommends the use of these criteria for the East Anglia TWO noise assessment, since they represent the most recent and relevant criteria. Popper et al. (2014) has been used within the underwater noise assessment. Details of the noise assessment can be found in section Marine Management Organisation 07/12/2017 Scoping Response The MMO recommends the use of the National Marine Fisheries Service (NMFS, 2016) thresholds and criteria for the modelling of underwater noise from piling activity as these are the most recent guidelines available. Noted, details of the noise assessment can be found in section The Planning Inspectorate 20/12/2017 Scoping Response No justification has been provided to support scoping the impacts of changes in fishing activity during construction and decommissioning out from assessment. In the absence of information such as evidence demonstrating clear agreement with relevant statutory bodies, the Inspectorate is not in a position to agree to scope this out. Accordingly, the ES should include an assessment of this matter Changes in fishing activity during construction and decommissioning are assessed in sections and respectively. The Planning Inspectorate 20/12/2017 Scoping Response Physical disturbance and temporary loss of seabed habitat, spawning or nursery grounds during intrusive works during operation; The Inspectorate agrees that this matter can be scoped out on the basis that intrusive works that would be undertaken in the operational phase would be related to maintenance activities, and the Inspectorate considers that this would be unlikely to be of a scale that would result in significant effects to these receptors. The Inspectorate notes that an Outline Offshore Operations and Maintenance Plan is likely to be submitted with the DCO application (paragraph 183 of the Scoping Report). We assume that An Outline Offshore Operations and Maintenance Plan (OOOMP) will be submitted as part of the Development Consent Order (DCO) application. EA1N-DEVWF-ENV-REP-IBR Chapter 10 Fish and Shellfish Ecology Page 4

15 Consultee Date/ Document Comment Response / where addressed in the PEIR this plan will include measures designed to reduce potential impacts and recommend that the Applicant seeks agreement on the plan from the MMO. The Planning Inspectorate 20/12/2017 Scoping Response Permanent habitat loss during construction and decommissioning; The Inspectorate agrees that this matter can be scoped out on the assumption that habitat lost during construction will be considered as a temporary impact, and that any habitat that is permanently lost following construction will be assessed as part of the operational impact assessment. Noted, this has been scoped out of the assessment. The Planning Inspectorate 20/12/2017 Scoping Response Underwater noise impacts to hearing sensitive species during foundation piling during operation and decommissioning; The Inspectorate agrees that this matter can be scoped out in respect of operation and decommissioning on the basis that piling would only take place during the construction phase and this will be assessed. Noted, this has been scoped out of the assessment. The Planning Inspectorate 20/12/2017 Scoping Response Introduction of wind turbine foundations, scour protection and hard substrate during construction and decommissioning; The Inspectorate agrees that this matter can be scoped out on the basis that this matter would be assessed as part of the operational impact assessment. Noted, this has been scoped out of the assessment. The Planning Inspectorate 20/12/2017 Scoping Response Electromagnetic fields during construction and decommissioning; Due to the nature of the construction and likely decommissioning works required for the Proposed Development the Inspectorate agrees that significant effects are unlikely to be attributed to EMFs during these phases and can be scoped out. Noted, this has been scoped out of the assessment. EA1N-DEVWF-ENV-REP-IBR Chapter 10 Fish and Shellfish Ecology Page 5

16 Consultee Date/ Document Comment Response / where addressed in the PEIR The Planning Inspectorate 20/12/2017 Scoping Response Cumulative permanent habitat loss during construction; The Inspectorate agrees that this matter can be scoped out on the assumption that habitat lost during construction will be considered in the EIA as a temporary impact, and that any habitat that is permanently lost following construction will be considered under cumulative operational impacts. Noted, this has been scoped out of the assessment. The Planning Inspectorate 20/12/2017 Scoping Response Transboundary impacts during all phases; The Inspectorate agrees that this matter can be scoped out in the knowledge that the distribution of fish and shellfish species is independent of national geographical boundaries and on the understanding that the assessment will take into account fish stocks and populations distribution irrespective of national jurisdictions. Noted, this has been scoped out of the assessment. The Planning Inspectorate 20/12/2017 Scoping Response It is not clear why only designated sites with the listed interest features will be considered in the PEI (and HRA), particularly when it is subsequently stated that there are no Special Areas of Conservation (SACs) designated for those features within 50km of the windfarm site. The species listed are the only Annex II marine / diadromous species relevant to UK waters, therefore any sites considered for this topic would have to include these. Although it is considered unlikely that there could be effects on sites designated for fish these were referenced for completeness. A full HRA screening exercise was undertaken subsequent to Scoping and all SACs screened out with regard to potential for likely significant effect. EA1N-DEVWF-ENV-REP-IBR Chapter 10 Fish and Shellfish Ecology Page 6

17 Consultee Date/ Document Comment Response / where addressed in the PEIR The Planning Inspectorate 20/12/2017 Scoping Response The study area for this assessment should be defined according to the relevant receptors that may experience impacts by the Proposed Development and the rationale should be explained in the PEI. No reference is made to the cable corridor AoS. The PEI should include an assessment of any impacts from the Proposed Development which could result in significant effects to designated sites. The study area has been defined and justified in section Section details any designated sites and species which may be impacted by the proposed East Anglia ONE North project, additionally, species of Conservation Interest are included within the impact assessment. The Planning Inspectorate 20/12/2017 Scoping Response The Inspectorate has been made aware of guidance referenced by the MMO in Section 9 of their scoping response (see Appendix 2 of this Opinion). The Applicant should take this into account in undertaking their assessment of the potential impacts of noise on fish. Noted, this guidance has been taken into consideration. Ongoing public consultation has been conducted through a series of Public Information Days (PIDs) and Public Meetings. PIDs have been held throughout Suffolk in November 2017, March 2018 and June / July 2018 with further events planned in A series of stakeholder engagement events were also undertaken in October 2018 as part of consultation phase 3.5. These events were held to inform the public of potential changes to the onshore substation location. This consultation aims to ensure that concerns are well understood and that site specific conditions can be taken into account, where practicable. Details of the consultation phases are discussed further in Chapter 5 EIA Methodology. Table 10.2 shows public consultation feedback pertaining to fish and shellfish ecology. Full details of the proposed East Anglia ONE North project consultation process will be presented in the Consultation Report, which will be submitted as part of the DCO application. EA1N-DEVWF-ENV-REP-IBR Chapter 10 Fish and Shellfish Ecology Page 7

18 Table 10.2 Public Consultation Responses relevant to Fish and Shellfish Ecology Topic Phase 1 Response / where addressed in the PEI None n/a Phase 2 Effects on marine life Effects on breeding grounds Potential impacts on all fish and shellfish ecology receptors during the construction, operation and decommission of the proposed East Anglia ONE North project are assessed in sections and Phase 3 Damage to marine environment Please see above. Phase 3.5 Impacts on marine life Please see above 10.3 Scope Study Area The proposed East Anglia ONE North project is encompassed within International Council for the Exploration of the Sea (ICES) Southern North Sea Division (IVc) statistical rectangles 1. The East Anglia ONE North windfarm site and part of the offshore cable corridor are within 33F2 and the near shore sections of the offshore cable corridor lie within 33F1, as shown in Figure Fishing stocks are managed by ICES division and quotas are allocated per rectangle. ICES rectangles are the smallest spatial unit used to collate commercial fisheries data and the data from certain national and international fish surveys. Both commercial fisheries data and data gathered from various national and international fish surveys are recorded, collated and analysed using the ICES rectangles within each division. Given the availability of broad scale data sets at the level of ICES rectangles, it is appropriate to define the study area using these. Therefore the study area used for the bulk of this assessment (defined as the local study area) is the area encompassed by 1 The boundaries of each ICES rectangle aligns to 0.5 latitude by 1.0 longitude, giving whole rectangle dimensions of approximately 30 by 30 nautical miles (nm), at UK latitudes. EA1N-DEVWF-ENV-REP-IBR Chapter 10 Fish and Shellfish Ecology Page 8

19 rectangles 33F1 and 33F2. The regional study area includes the wider Southern North Sea. Where appropriate, broader geographic study areas have been used for the purpose of the fish and shellfish environmental baseline description and impact assessment. This has particular relevance to life history aspects such as the distribution of spawning grounds and migration Worst Case The design of the proposed East Anglia ONE North project (including number of wind turbines, layout configuration, requirement for scour protection, electrical design, etc.) is not yet fully determined, and may not be known until sometime after the DCO has been granted. Therefore, in accordance with the requirements of the Project Design Envelope (also known as the Rochdale Envelope) approach to EIA (Planning Inspectorate 2018) (as discussed in Chapter 5 EIA Methodology), realistic worst case scenarios in terms of potential effects upon fish and shellfish ecology are adopted to undertake precautionary and robust impact assessment. Definition of the worst-case scenarios has been made from consideration of the proposed East Anglia ONE North project that is presented in Chapter 6 Project Description, alongside the mitigation measures that have been embedded in the design (section ) Offshore Infrastructure The Applicant is considering several different sizes of wind turbine between 250 and 300m blade tip height for the proposed East Anglia ONE North project. To achieve the maximum 800MW installed capacity there would be between 67 (250m) and 42 (300m) turbines. In addition, up to four offshore electrical platforms, one operation and maintenance platform, one meteorological mast, up to 20 buoys (LiDAR, wave recording and guard) plus offshore cables (inter-array, platform link and export cables) are part of the worst case. A realistic worst case scenario for the potential impacts of the proposed East Anglia ONE North project on fish and shellfish receptors has been identified by using the project design envelope parameters described in Chapter 6 Project Description. EA1N-DEVWF-ENV-REP-IBR Chapter 10 Fish and Shellfish Ecology Page 9

20 The design parameters which constitute the worst case scenario for fish and shellfish ecology are presented by impact in Table which outlines the worst case scenarios for each identified impact. Where percentage areas affected have been calculated, these are based on a total windfarm site area of 208km 2 and an offshore cable corridor area of 133km 2 which results in a total offshore development area for the assessment of 341km 2. EA1N-DEVWF-ENV-REP-IBR Chapter 10 Fish and Shellfish Ecology Page 10

21 Table 10.3 Realistic Worst case scenarios Impact Parameter Rationale Construction Impact 1 Physical disturbance and temporary loss of seabed habitat, spawning or nursery grounds during intrusive works. Worst case scenario for an individual foundation would be 250m wind turbines with four-legged jacket suction caisson foundations. Preparation area per 250m wind turbine = 6,947.63m 2 Seabed preparation area for East Anglia ONE North offshore development area: Seabed preparation for 67 x 250m wind turbines on four-legged jackets with suction caissons = 465,491m 2. Four offshore electrical platforms and one operation and maintenance platform each with a seabed preparation area of 37,312m 2 = 186,560m 2. One operational meteorological mast assumed to be the same as seabed preparation for one 250m wind turbine four-legged jacket on suction caissons which is conservative = 6,948m 2 Pre-lay grapnel run with a 20m wide swathe along the whole length of cable routes would disturb the following areas: The temporary disturbance relates to seabed preparation and cable installation. The footprint of infrastructure including cable protection is assessed as a permanent impact in O&M impact 1. It should be noted that the seabed preparation area for foundations is less than the footprint of the foundation scour protection. The area affected by sand wave levelling in the windfarm site would be encompassed by the pre-lay grapnel run while the area affected in the offshore cable corridor would differ at up to 800,000m 2 due to a wider (60m) dredge being required. 152km export cable = 3,040,000m 2 (approximately 2.3% of the offshore cable corridor) and would occur over an up to one year period. 200km of inter-array cable = 4,000,000m 2 75km of platform link cable = 1,500,000m 2 Sand wave levelling in the offshore cable corridor would result in an area of up to 800,000m 2 being disturbed. Jack up barge seabed footprint for 67 foundations (based on a jack up barge footprint of 3,000m 2 and three movements per foundation) the EA1N-DEVWF-ENV-REP-IBR Chapter 10 Fish and Shellfish Ecology Page 11

22 Impact Parameter Rationale maximum disturbance would be 603,000m 2. Boulder clearance around wind turbine foundations 600 boulders of up to 300mm diameter = 180m 2 Worst case scenario total disturbance footprint =10,602,179m 2, which constitutes 3% of the maximum offshore development area. Any other works associated with cable installation would be encompassed by the footprints outlined above. Impact 2 Increased suspended sediments and sediment redeposition The worst case scenario would involve the maximum amount of sediment disturbance through preparation of the seabed, including: Seabed preparation 67 x 250m wind turbines on four-legged jacket suction caisson foundations 23,731.9m 3 per wind turbine totalling 1,590,036m 3. Eight-legged jacket suction caisson foundations for up to four offshore electrical and one operations and maintenance platform would result in a maximum sediment release into the water column of 668,800m 3. Four-legged suction caisson foundation for one meteorological mast. Therefore, the maximum possible amount of sediment released into the water column would be up to 23,732m 3. Sand wave levelling The total volume of sediment excavated during sand wave levelling would not exceed the following: Export cable 500,000m 3 Seabed preparation (dredging using a trailer suction hopper dredger and levelling layer) may be required up to a sediment depth of 5m. The worst case considers the maximum volumes for the project. The worst case would be defined by m wind turbines mounted on four-legged jacket suction caisson foundations. The meteorological mast would be installed on foundations which, in the worst case for sediment disturbance, would be four-legged jacket suction caisson foundations. As a worst case, the figure for seabed preparation for a 250m wind turbine four-legged jacket on suction caissons has been used and is considered conservative. The worst case with regard to sediment disturbance during installation of offshore EA1N-DEVWF-ENV-REP-IBR Chapter 10 Fish and Shellfish Ecology Page 12

23 Impact Parameter Rationale Platform link cable 150,000m 3 Inter-array cables 400,000m 3 Trenching / dredging requirements There may also be a requirement for trenching in the near shore area around the HDD punch-out location during the installation of export cables. Based on EA1 values, although with adequate redundancy built in, it is assumed that up to 5% (3.8km) of each cable corridor will require dredging to a max of 20m wide by 5m deep which = 800,000m 3 for both cables. platform foundations (including four electrical and one operation and maintenance) would be from installation of eight-legged jacket suction caissons which would require the excavation of up to 668,000km 3. Total volume of sediment affected in the windfarm site 2,832,568m 3 Total volume of sediment affected in the offshore cable corridor 1,300,000m 3 The total maximum excavation requirement for all infrastructure within the East Anglia ONE North offshore development area would be 4,132,568m 3. Drill Arisings Should the installation of monopiles or jackets using pin piles be required, drilling may also be undertaken which would release subsurface materials into the water column. Wind turbine foundations based on worst case volume associated with m wind turbines (45 m depth 13m diameter) = 42,146m 3 Meteorological mast based on arisings from a 250m wind turbine monopile foundation which is conservative: 5,972m 3 Offshore electrical and accommodation platforms: 43,210m 3 Total drill arisings = 91,328m 3 EA1N-DEVWF-ENV-REP-IBR Chapter 10 Fish and Shellfish Ecology Page 13

24 Impact Parameter Rationale Sub-surface sediments have a different physical composition to nearsurface sediments and may therefore be more widely dispersed by tidal currents. However, the volumes involved are far smaller than seabed preparation for four-legged jacket suction caisson foundations (Chapter 7 Marine Geology, Oceanography and Physical Processes) and therefore it is considered that installation of four-legged jacket suction caisson foundations is the worst case scenario for re-suspension of sediments. As stated in section of Chapter 9 Benthic Ecology, it is difficult to accurately estimate the volumes of sediment likely to be affected during cable installation however it is likely to be much less than that affected during foundation installation. Therefore, this figure has not been calculated. It should be noted that seabed preparation is less likely to be required for piled foundations and, if required, would be significantly less than described above. Therefore, the volume of drill arisings and seabed preparation outlined above are not cumulative. Impact 3 Remobilisation of contaminated sediment during intrusive works The worst case scenario relates to activities that involves the increase of SSCs as set out above. As above Impact 4 Underwater noise impacts to hearing sensitive species during foundation piling Number of wind turbines Up to 67 (250m devices) or 53 (300m devices) Number of offshore platforms 4 x Offshore electrical EA1N-DEVWF-ENV-REP-IBR Chapter 10 Fish and Shellfish Ecology Page 14

25 Impact Parameter Rationale 1 x Met mast 1 x construction, operation and maintenance = 6 Wind turbine foundation options Monopile = piled 4-leg jacket = pin-piles Hammer piled platforms represent the worstcase scenario for underwater noise. Platform foundation options Electrical platforms = jacket with pin-piles Met mast = monopile or jacket with pin-piles Construction, operation and maintenance platform = jacket with pin-piles Proportion of foundations that are piled 100% Number of piles per foundation Wind turbines = 1 monopile or 4 pin-piles The maximum proportion of hammer piled foundations represents the worst-case scenario for underwater noise. Electrical platforms = 8 pin-piles per platform Met mast = 1 monopile or 4 pin-piles Construction, operation and maintenance platform = 8 pin-piles per platform Number of piles for wind turbines 250m = 67 monopiles or 268 pin-piles Maximum number of pin-piles for all wind turbine foundations is m = 53 monopiles or 212 pin-piles Number of piles for offshore platforms Offshore electrical platforms = 4 x 8 pin-piles = 32 pin-piles Maximum number of pin-piles for all platform foundations is 44 Met mast = 1 monopile or 4 pin-piles EA1N-DEVWF-ENV-REP-IBR Chapter 10 Fish and Shellfish Ecology Page 15

26 Impact Parameter Rationale Construction, operation and maintenance platform = 8 pin-piles Total number of piled foundations Maximum number of pin-piles = 268 (250m) + 44 (platforms) = 312; Or Maximum number of monopiles = 67 (250m devices) + 1 (met mast) = 68; plus 40 pin piles for offshore platforms Hammer energy monopiles Maximum hammer energy = 4,000kJ for 300m turbines with 15m diameter monopile. Starting hammer energy of 400kJ will be used for 10 minutes. Ramp up will then be undertaken for at least 20 minutes. Hammer energy pin-piles Maximum hammer energy = 2,400kJ for 4.6m diameter pin-piles (300m devices or platforms). Starting hammer energy of 240kJ will be used for 10 minutes. Ramp up will then be undertaken for at least 20 minutes. Pile diameter monopiles Maximum monopile diameter of 15m for 300m wind turbines. Pile diameter pin-piles Maximum pin-pile diameter of 4.6m for 300m wind turbines and platforms (electrical and construction, operation and maintenance platforms). Total piling time per wind turbine foundation for monopiles (including soft-start and ramp-up and providing allowance for issues such as low blow rate, refusal, etc.) 325 minutes (5.42hrs) x 53 (300m) monopiles = 287 hours This is the worst-case scenario with potential underwater noise impacts greater than 3,000kJ for 250m wind turbine monopile. This is the worst-case scenario with potential underwater noise impacts greater than 1,800kJ for 250m wind turbine pin-piles. 15m diameter is the worst-case scenario for monopiles, with potential underwater noise impacts greater than 13m diameter monopile for 250m wind turbines and 8m diameter monopile for met mast. 4.6m diameter is the worst-case scenario for pin-piles, with potential underwater noise impacts greater than 4m diameter for 250m wind turbines and 2.5m diameter pin-piles for met mast (confirmed with INSPIRE light assessment). The maximum hammer piling duration of 287 hours (up to 11.9 days) represents the temporal worst-case scenario for the installation of monopiles for the 300m wind turbines (this includes 10 minute soft-start and 20 minute ramp-up). This is greater than the maximum EA1N-DEVWF-ENV-REP-IBR Chapter 10 Fish and Shellfish Ecology Page 16

27 Impact Parameter Rationale Total piling time per wind turbine foundation for pin-piles (including soft-start and ramp-up and providing allowance for issues such as low blow rate, refusal, etc.) 199 minutes (3.32 hours) x 4 pin-piles x 53 (300m) = hours Total piling time per platform foundation (including soft-start and ramp-up and providing allowance for issues such as low blow rate, refusal, etc.) 199 minutes x 8 pin-piles x 4 offshore electrical platforms = 106.1hrs 199 minutes x 8 pin-piles x 1 construction, operation and maintenance platform = 26.5hrs 127 minutes x 4 pin-piles x 1 Met mast = 8.5hrs Total = 141 hours (up to 6 days) hammer piling duration of hours for the installation of monopiles for the 250m wind turbines (110 minutes, including soft-start and ramp-up x 67). The maximum hammer piling duration of hours (up to 29.3 days) represents the temporal worst-case scenario for the installation of pinpiles for the 300m wind turbines (this includes 10 minute soft-start and 20 minute ramp-up). This is greater than the maximum hammer piling duration of hours for the installation of pinpiles for the 250m wind turbines (127 minutes, including soft-start and ramp-up x 67 x 4). The maximum hammer piling duration of 141 hours (up to 6 days) represents the temporal worst-case scenario for the installation of the platforms (including soft-start and ramp-up). Impact 5 Underwater noise impacts to hearing sensitive species due to other Maximum total active piling time for wind turbines and platforms hours (35.2 days) Cable installation The intention is to bury cables, however in areas where burial is not possible, the cable will be surface laid with cable protection. Additional methods considered include: Based on the worst-case scenario of pin-piles for wind turbines (up to 29.3 days) and platforms (up to 6 days). Underwater noise and vibration associated with seabed preparation, rock dumping, cable installation and construction vessels. This would result in the greatest noise impacts as a result of project construction activities other than piling EA1N-DEVWF-ENV-REP-IBR Chapter 10 Fish and Shellfish Ecology Page 17

28 Impact Parameter Rationale activities (vessels, seabed preparation, cable installation etc.) Ploughing; Jetting; Trenching; and Vertical injector. Maximum length of cables: Inter-array cables: 200km Platform link cables:75km Export cables: 152km. Vessels Maximum number of vessels on site at any one time: 74 Maximum number of individual vessels during construction: 3,335 for foundation installation. Impact 6: Underwater Noise Impacts to Hearing Sensitive Species due to UXO Clearance Underwater noise associated with UXO clearance Number of UXO: Up to 80 Type and size of UXO: Up to 700g (net explosive quantities NEQ) Numbers based on East Anglia ONE UXO survey, but a detailed UXO survey will be completed prior to construction. Impact 7 Changes in fishing activity See Chapter 13 Commercial Fisheries Changes in fish stocks of commercial importance as a result of changes in fishing activity. Operation Impact 1 Permanent habitat loss The maximum possible seabed footprint of the project including scour protection. The maximum size of the project footprint is based on the following: The scenario described gives rise to the greatest area of permanent seabed habitat loss. Areas impacted by scour would be changed irreversibly and would therefore count as habitat EA1N-DEVWF-ENV-REP-IBR Chapter 10 Fish and Shellfish Ecology Page 18

29 Impact Parameter Rationale Windfarm Site Infrastructure 60m diameter gravity-based foundation and scour protection footprints together are calculated as 25,446.9m 2 per foundation (see Chapter 6 Project Description Table 5.7). Therefore, for 53 foundations (see adjacent notes column) the maximum area of baseline habitat lost would be 1,348,686m 2 which is considered the worst case. The maximum area of baseline habitat lost due to installation of offshore electrical and operation and maintenance platforms on four-legged jackets with suction caissons with associated scour protection would amount to 37,980m 2 per platform. There would be up to five such structures totalling 189,900m 2. The gravity-base foundation and scour protection for one meteorological mast would be 3,142m 2. Cable Protection in the Windfarm Site Cable protection for up to 7.5km of platform link cable due to ground conditions of up to 63,750m 2. Additionally, up to 40,800m 2 of cable protection would be required for unburied platform link cables at cable crossings. Cable protection for up to 24.8km of inter-array cables which amounts to 210,800m 2. Therefore, a total area of up to 315,350m 2 of cable protection would be required in the windfarm site. Total Windfarm Site Infrastructure Total footprint during operation within the East Anglia ONE North windfarm site which could be subject to permanent habitat loss is therefore loss. The worst case for the area lost due to meteorological mast installation has been determined from the area required for a 250m wind turbine gravity based foundation which is considered conservative. EA1N-DEVWF-ENV-REP-IBR Chapter 10 Fish and Shellfish Ecology Page 19

30 Impact Parameter Rationale 1,857,078m 2 which constitutes 0.9% of the windfarm site. Export Cable Cable protection due to an inability to bury export cables would result in a footprint of up to 129,200m 2. Protection associated with cable crossing for export cables would result in a footprint of up to 46,240m 2. Total footprint which could be subject to permanent habitat loss during operation of the export cables is therefore 175,440m 2 (0.13% of the offshore cable corridor area). Total The overall total footprint which could be subject to permanent habitat loss would therefore be 2,032,518m 2 (0.59% of the offshore development area). Impact 2 Increased suspended sediments and sediment redeposition The maximum amount of suspended sediment that would be released into the water column due to changes in tidal regime around infrastructure has been calculated based findings verified by field measurements (see Chapter 7 Marine Geology, Oceanography and Physical Processes section ). This has been calculated as a worst case scour volume under a 50-year return period event of about 5,000m 3 for an individual foundation of similar type and size to a worst case 53m gravity-based structure. Therefore, for 67 wind turbine foundations the maximum amount of scour material released into the water column would be 335,000m 3. The need for and type of scour protection would not be determined until the wind turbine location and associated foundation types are known, therefore the worst case scenario would involve the use of no scour protection. Of all the foundation options under consideration 67 53m diameter gravity-base structures would cause the greatest amount of scour. Assumptions for scour produced from Chapter 7 Marine Geology, Oceanography and Physical Processes). Impact 3 Re- The worst case scenario relates to activities that involves the increase of As above EA1N-DEVWF-ENV-REP-IBR Chapter 10 Fish and Shellfish Ecology Page 20